Vertebral implants and methods for installation thereof

ABSTRACT

Embodiments herein are generally directed to vertebral implants and implant trials for use with vertebral implant assemblies. In some embodiments, these implants and implant trials may be used in conjunction with corpectomy procedures.

CROSS-REFERENCE TO RELATED REFERENCES

The present application is a continuation-in-part application thatclaims priority to U.S. Ser. No. 14/580,273, filed Dec. 23, 2014, whichis hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to vertebral implants, implant trials, andmethods used to install these devices.

BACKGROUND OF THE INVENTION

Many types of spinal irregularities can cause pain, limit range ofmotion, or injure the nervous system within the spinal column. Theseirregularities can result from, without limitation, trauma, tumor, discdegeneration, and disease. One example of a spinal irregularity isspinal stenosis, the narrowing of a spinal canal, which can result inthe compression of spinal nerves such as the spinal cord or caudaequina. In turn, the nerve compression can result in pain, numbness, orweakness. Spinal stenosis may be caused by one or more conditions suchas development of bone spurs, thickening of ligaments, fractures, anddisc degeneration (e.g., due to arthritis).

Treatment of spinal stenosis can include, for example, a surgicalprocedure to expand the spinal canal by modifying or removing at least apart of a vertebra, as in a laminoplasty, laminectomy, or corpectomy. Ina corpectomy, the vertebral bodies of one or more vertebrae adjacent tothe compressed nerve can be removed, thereby expanding the spinal canal.Subsequently, a cage or other prosthetic may be inserted into theresulting cavity and may be used to subsequently stabilize the spine,either alone or in combination with one or more additional devices suchas rods, screws, and/or plates.

SUMMARY OF THE INVENTION

Some embodiments herein are directed to a polyaxial endplate assemblythat can include a locking member comprising a neck portion extendingfrom a rounded head portion, the neck portion comprising a tapered slotextending therethrough; an articulable plate member comprising a plateportion extending from a rounded compressible body portion, the roundedcompressible body portion defining a cavity configured to receive therounded head portion of the locking member therein and an apertureconfigured to receive the neck portion of the locking membertherethrough; a receiving member comprising an axial conduit comprisinga constant diameter section and a variable diameter section, first andsecond tapered holes defining a tapered channel which intersects theconduit, and a receptacle which intersects the tapered channel, whereinthe variable diameter section is configured to receive the roundedcompressible body portion of the articulable plate member therein; awedge member comprising a tapered transverse cross section andconfigured to be received within the channel of the receiving member;and a securing element configured to be received within the receptacleof the receiving member.

Other embodiments herein are directed to a polyaxial endplate assemblythat can include a locking member comprising a neck portion extendingfrom a rounded head portion, the neck portion comprising a tapered slotextending therethrough; an articulable plate member comprising a plateportion extending from a rounded body portion, the rounded body portioncomprising a plurality of tabs defining a concave cavity and a centralaperture; a receiving member comprising an axial conduit comprising aconstant diameter section and a variable diameter section, a taperedchannel which intersects the axial conduit, and a receptacle whichintersects the tapered channel; a wedge member comprising a taperedtransverse cross section; and a securing element configured to stabilizean orientation of the plate member relative to the receiving member.

Yet other embodiments herein are directed to a polyaxial endplateassembly that can include a locking member comprising a neck portionextending from a rounded head portion, the neck portion comprising atapered slot extending therethrough; an articulable plate membercomprising a plate portion extending from a rounded body portion, therounded body portion comprising a plurality of tabs defining a concavecavity and a central aperture; a receiving member comprising an axialconduit comprising a constant diameter section and a variable diametersection, first and second tapered holes defining a tapered channel whichintersects the conduit, and a receptacle which intersects the taperedchannel; a wedge member configured to apply a force to the receivingmember and the locking member; and a securing element configured toapply a force to the wedge member.

Some embodiments herein are directed to a method of installing avertebral implant assembly that can include providing a vertebralimplant assembly that can include a vertebral implant comprising a firstengagement member; and a first polyaxial endplate assembly comprising afirst receiving member having a tapered channel, a first articulableplate member articulably disposed within the receiving member, a firstlocking member disposed within the articulable plate member, and a firstwedge member slideably disposed within the tapered channel; coupling thefirst polyaxial endplate assembly with the first engagement member; andapplying force to the first wedge member to stabilize an orientation ofthe articulable plate member of the first polyaxial assembly relative tothe vertebral implant.

Other embodiments herein are directed to a method of installing avertebral implant assembly that can include providing a vertebralimplant comprising a first polyaxial endplate assembly and a secondpolyaxial endplate assembly, wherein the first polyaxial endplateassembly comprises a first articulable plate member and a first wedgemember and the second polyaxial endplate assembly comprises a secondarticulable plate member and a second wedge member; applying force tothe first wedge member to stabilize an orientation of the firstarticulable plate member relative to the vertebral implant; and applyingforce to the second wedge member to stabilize an orientation of thesecond articulable plate member relative to the vertebral implant.

Yet other embodiments herein are directed to a method of installing avertebral implant assembly that can include providing an expandablevertebral implant comprising a first engagement member and a secondengagement member; coupling a first polyaxial endplate assembly with thefirst engagement member, wherein the first polyaxial endplate assemblycomprises a first receiving member, a first articulable plate member,and a first wedge member; coupling an second polyaxial endplate assemblywith the second engagement member, wherein the second polyaxial endplateassembly comprises a second articulable plate member and a second wedgemember; expanding the vertebral implant from a first height to a secondheight; applying force to the first wedge member to stabilize anorientation of the first articulable plate member of the first polyaxialendplate assembly relative to the vertebral implant; and applying forceto the second wedge member to stabilize an orientation of the secondarticulable plate member of the second polyaxial endplate assemblyrelative to the vertebral implant.

Some embodiments herein are directed to a polyaxial endplate assemblythat can include an articulable plate member comprising a plate portionextending from a rounded compressible body portion, the body portiondefining a cavity therein; a clamp assembly comprising first and secondclamp members each comprising a central receptacle and an interiorsurface configured to engage the plate member, and a securing elementconfigured to be received within the receptacles of the first and secondclamp members; and a receiving member comprising a convex exteriorsurface configured to be received within the cavity of the body portion.

Other embodiments herein are directed to a polyaxial endplate assemblythat can include an articulable plate member comprising a plate portionextending from a rounded body portion, the body portion comprising aplurality of tabs and defining a cavity therein; first and second clampmembers each comprising a central receptacle and an interior surfaceconfigured to engage the plate member; a receiving member comprising arounded portion configured to be received within the cavity of the bodyportion; and a securing element configured to stabilize an orientationof the plate member relative to the receiving member.

Yet other embodiments herein are directed to a polyaxial endplateassembly that can include an articulable plate member comprising a plateportion extending from a rounded body portion, the body portioncomprising a plurality of tabs and defining a cavity therein; first andsecond clamp members each comprising an interior surface configured toengage the plate member and further comprising a central protrusionhaving a receptacle therein; a receiving member comprising a roundedportion configured to be received within the cavity of the body portion;and a securing element configured to be received within both receptaclesof the first and second clamp members.

Some embodiments herein are directed to a method of installing avertebral implant assembly that can include providing a vertebralimplant assembly that can include a vertebral implant comprising a firstengagement member; and a first polyaxial endplate assembly comprising afirst receiving member, a first articulable plate member, and a firstclamping assembly, wherein the first receiving member is at leastpartially disposed within a cavity of the first articulable plate memberand the first clamp assembly is engaging a body portion of the firstarticulable plate member; coupling the first polyaxial endplate assemblywith the vertebral implant; and applying a force to the firstarticulable plate member to stabilize an orientation of the firstarticulable plate member relative to the vertebral implant.

Still other embodiments herein are directed to an endplate trial thatcan include a coupling element configured to reversibly engage at leasta portion of a vertebral implant device.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating certain embodiments of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1A illustrates a cross-sectional view of a polyaxial endplateassembly as described herein;

FIGS. 1B-D illustrate perspective views of a polyaxial endplate assemblyas described herein;

FIG. 1E illustrates a perspective view of a polyaxial endplate assemblyengaged with a vertebral implant as described herein;

FIG. 2A illustrates a perspective bottom view of a polyaxial endplateassembly as described herein;

FIG. 2B illustrates a cross-sectional view of a polyaxial endplateassembly as described herein;

FIG. 2C illustrates a cross-sectional view of a clamp assembly engagingan articulable plate member as described herein;

FIG. 2D illustrates a perspective view of a clamp assembly as describedherein;

FIG. 3A illustrates a perspective view of an endplate trial as describedherein;

FIG. 3B illustrates a cross-sectional view of an endplate trial asdescribed herein;

FIG. 3C illustrates a perspective view of an endplate trial as describedherein;

FIG. 3D illustrates an endplate trial and an expandable trial assemblyas described herein;

FIG. 3E illustrates a cross-sectional view of an endplate trial engagedwith an expandable trial assembly as described herein;

FIG. 3F illustrates a perspective view of an endplate trial engaged withan expandable trial assembly as described herein;

FIG. 4A illustrates a perspective view of an endplate trial as describedherein;

FIG. 4B illustrates a cross-sectional view of an endplate trial engagedwith an expandable trial assembly as described herein;

FIG. 4C illustrates a perspective bottom view of an endplate trial asdescribed herein;

FIG. 4D illustrates a perspective view of an endplate trial engaged withan expandable trial assembly as described herein;

FIGS. 5-10 illustrate alternative embodiments of endplate trials asdescribed herein.

FIG. 11A illustrates a view of an alternative expandable vertebralimplant in accordance with some embodiments;

FIG. 11B illustrates an exploded view of the alternative expandablevertebral implant of FIG. 11A;

FIG. 12 illustrates a side cross-sectional view of a polyaxial endplateassembly of the implant of FIGS. 11A and 11B; and

FIG. 13 shows a top cross-sectional view of the polyaxial endplateassembly of FIG. 12.

DETAILED DESCRIPTION

In a corpectomy procedure, a spinal canal can be expanded, and pressureon a compressed nerve can be relieved, by partially or completelyremoving one or more vertebral bodies adjacent to the compressed nerve.One or more intervertebral discs and other associated materials may alsobe removed. An implant (e.g., a cage, spacer, vertebral bodyreplacement, or other prosthetic) may be inserted into the resultingcavity to subsequently stabilize the spine. In some instances, theimplant can include an optionally-expandable body coupled to superiorand inferior endplates that have been selected to match the contours ofthe vertebral cavity. Prior to insertion, a surgeon or otherpractitioner may approximate the appropriate size and lordotic orkyphotic angle of the endplates (e.g., via imaging and/or physicalmeasurement devices such as a caliper or implant trial), select theendplates that most closely match the desired angles, and assemble theimplant by connecting the selected endplates with the implant body. Oncethe implant is assembled and inserted into the vertebral cavity, thesurgeon may be unable to make further in-situ adjustments to the anglesof the endplates. A disparity between the angles of the endplates andthe angles of the adjacent vertebral bodies can result in subsidence orsagittal imbalance. Accordingly, disclosed herein are new and improvedmodular vertebral implants and assemblies having polyaxial endplates,the angles of which can be pivotably adjusted after assembly and/orimplantation.

Components of all of the devices disclosed herein can be made ofmaterials known to those skilled in the art, including metals (e.g.,titanium), metal alloys (e.g., stainless steel and cobalt-chromium),ceramics, polymers (e.g., poly ether ether ketone (PEEK), polyphenylenesulfone (PPSU), polysulfone (PSU), polycarbonate (PC), polyetherimide(PEI), polypropylene (PP), polyacetals, or mixtures or co-polymersthereof), allograft, and/or combinations thereof. In some embodiments,the devices may include radiolucent and/or radiopaque materials. Thecomponents can also be machined and/or manufactured using techniquesknown to those skilled in the art. For example, polymeric components maybe injection-molded or blow-molded. Additionally, the devices disclosedherein may be used together with materials that encourage bone growth,such as bone graft material, demineralized bone matrix, bone chips,and/or bone morphogenetic proteins. In some embodiments, these materialsmay advantageously be packed into hollow areas of the devices describedherein.

As used herein the terms “proximal” and “distal” are utilized generallywith reference to an implant or other device with which the polyaxialendplate assemblies and endplate trial assemblies described herein maycouple. For example, the end of an endplate assembly that is closer tothe implant or other device, after the entire assembly has been puttogether, may be referred to as the “proximal” end, whereas the end ofthe endplate assembly that is farther from the implant or other device(e.g., the end that may be configured to engage a vertebral body) may bereferred to as the “distal” end. Similarly, the terms “superior,”“inferior,” “top,” and “bottom,” and the like may be used herein fordescriptive purposes and do not limit the orientation(s) in which thedevices may be used. For example, those skilled in the art mayappreciate that a “superior” endplate may be installed in an inferiorposition, and vice versa. Accordingly, a feature described as being ontop may actually be oriented towards the bottom after installation.

In some embodiments, the present application describes a polyaxialendplate assembly that can be attached to or form part of an interbodyspacer such as a corpectomy device. The polyaxial endplate assembly cancomprise an endplate in the form of an articulatable plate member, areceiving member attachable to the corpectomy device for receiving thearticulable plate member, and a locking member received within thearticulatable plate member. The polyaxial endplate assembly can replacean endplate (such as reference numeral 20 in FIG. 2 of U.S. 2011/0251691to McLaughlin, herein incorporated by reference in its entirety).Advantageously, the articulatable plate member of the polyaxial endplateassembly is capable of pivoting and rotation, thereby accommodatingdifferent lordosis and kyphosis of a patient. The articulable platemember is capable of pivoting and rotating naturally relative to apatient's anatomy until it is secured in position via the lockingmember. These features are described below.

Turning now to FIGS. 1A-E, polyaxial endplate assembly 100 isillustrated in accordance with embodiments described herein. Asillustrated in FIG. 1A, the polyaxial endplate assembly 100 can includea locking member 2, an articulable plate member 4, a receiving member 6,a wedge member 8, and a securing element 10.

The locking member 2 can include a rounded head portion 12 and a neckportion 14 extending therefrom. The rounded head portion 12 can have aconvex outer surface. In some embodiments, the rounded head portion 12can include an at least partially spherical, spheroidal, or ovoidalouter surface. The outer diameter of the rounded head portion 12 canvary axially (e.g., can decrease in a proximal direction). The neckportion 14 of the locking member 2 can include a cylindrical outersurface. As illustrated in FIG. 1A, the neck portion 14 can also includea tapered slot 16 extending therethrough. The tapered slot 16 can definea trough that extends transverse or perpendicular to the longitudinalaxis 24 of the locking member 2. The tapered slot 16 can have a variableheight. For example, the height of the tapered slot 16, as measuredlongitudinally, can decrease as a depth of the tapered slot 16, asmeasured transversely, increases.

As illustrated in FIG. 1A, the locking member 2 can be hollow (e.g., caninclude a conduit 18 extending along a longitudinal axis 24 from adistal end 20 to a proximal end 22). The conduit 18 can include acircular transverse cross section. In some embodiments, the diameter ofthe conduit 18 can vary along at least a portion of the longitudinalaxis 24. In some embodiments, the conduit 18 can include a variablediameter section and a constant diameter section. As illustrated in FIG.1A, the variable diameter section can be disposed within the roundedhead portion 12 and the constant diameter section can be disposed withinthe neck portion 14. In these embodiments, the conduit 18 can define acavity within the rounded head portion 12 having a rounded longitudinalcross section, as illustrated in FIG. 1A. In other embodiments, thecavity can have an angular (e.g., conical) longitudinal cross section.In the neck portion 14 of the locking member 2, the conduit 18 candefine a hollow cylinder. Advantageously, the interaction between thelocking member 2 and the wedge member 8 fixes the angular position ofthe articulable plate member, as discussed further below.

The articulable plate member 4 can include a plate portion 26 extendingfrom a rounded body portion 28. The plate portion 26 can include a topor distal surface 34 and a central aperture 36, as illustrated in FIG.1B. The distal surface 34 may be configured to engage or contact avertebral body. Accordingly, the distal surface 34 may be contoured tocorrespond to the shape of a vertebral body. As illustrated, the distalsurface 34 can be planar. However, in other embodiments, the distalsurface 34 can be convex or concave. Additionally, the distal surface 34may include one or more features to enhance the interaction or frictionbetween the implant and the vertebral body or other bone feature. Forexample, the distal surface 34 can be roughened, and can include, forexample, a plurality of teeth, bumps, peaks, grooves, and/or knurling.The distal surface 34 can include at least one engagement member. Theengagement member can be configured to engage and/or apply force to avertebral body. For example, the engagement member can be a spike. Insome embodiments, the distal surface 34 can include a plurality ofengagement members. The engagement member(s) can advantageously preventsliding or other translational movement of the assembly afterinstallation within the vertebral space. In other embodiments, thedistal surface 34 can include an imaging member, such as one or moreradiographic markers.

As illustrated in FIG. 1A, the rounded body portion 28 of thearticulable plate member 4 can include a curved inner surface 42 and acurved outer surface 44. The curved inner surface 42 can define aconcave cavity 30 therein and can include an aperture 32 therethrough.The central aperture 36 of the plate portion 26 may lead into the cavity30. The cavity 30 can be configured to receive the rounded head portion12 of the locking member 2. The curved inner surface 42 may beconfigured to contact the outer surface of the rounded head portion 12of the locking member 2. The aperture 32 can be configured to receivethe neck portion 14 of the locking member 2 therethrough, and maytherefore have a diameter than is greater than an outer diameter of theneck portion 14. The aperture 32 may have a diameter that is less than amaximum diameter of the head portion 12 of the locking member 2, therebypreventing the locking member 2 from passing entirely through thearticulable plate member 4.

As illustrated in FIGS. 1C-D, the rounded body portion 28 can include aplurality of tabs 38. The tabs 38 can be separated by slots 40. Thenumber of tabs 38 making up the rounded body portion 28 can vary, andcan be, for example, in the range of from about two to about twelve. Insome embodiments, the tabs 38 and slots 40 may be equally sized andspaced. In other embodiments, the tabs 38 and/or slots 40 may be ofvariable sizes. Advantageously, the rounded body portion 28 may becompressible, bendable, flexible, and/or constrictable (e.g., a forcemay be applied to the tabs 38 which causes the tabs 38 to flex inward,thereby reducing the volume of the cavity 30). Additionally, the outersurface 44 of the articulable plate member 4 may include acircumferential groove 46 or thinned section at an intersection betweenthe body portion 28 and the plate portion 26. The circumferential groove46 may advantageously enhance the movement of the tabs 38 and theoverall flexibility of the rounded body portion 28, thereby enhancingengagement of the rounded body portion 28 with the locking member 2 andreceiving member 6.

As illustrated in FIGS. 1A-C, the receiving member 6 can include acylindrical side surface 68, a top surface 64 adjacent a distal end 58,and a bottom surface 65 adjacent a proximal end 60. The receiving member6 can also include a chamfered edge 66 between the side surface 68 andthe top surface 64. Additionally, the receiving member 6 can include anaxial conduit 48, first and second tapered holes 50, 52 defining atapered channel 56, and a receptacle 54 which intersects the taperedchannel 56. The axial conduit 48 can extend along a longitudinal axis62, illustrated in FIG. 1C, from distal end 58 to proximal end 60. Theaxial conduit 48 can include a circular transverse cross section. Insome embodiments, the diameter of the axial conduit 48 can vary along atleast a portion of the longitudinal axis 62. In some embodiments, theaxial conduit 48 can include a variable diameter section and a constantdiameter section. In some embodiments, the variable diameter section candefine a concave socket (e.g., having a rounded or curved longitudinalcross section) bounded by top surface 64, as illustrated in FIG. 1A. Inother embodiments, the socket can have an angular (e.g., conical)longitudinal cross section.

The first tapered hole 50 can be trapezoidal or rounded trapezoidal, asillustrated in FIGS. 1B-C. In some embodiments, the first tapered hole50 can be asymmetrical along a horizontal plane (e.g., the first taperedhole 50 may be defined by an upper wall and a lower wall, wherein thelower wall is steeper than the upper wall, or vice versa). In otherembodiments, it may be symmetrical. As illustrated in FIG. 1B, the firsttapered hole 50 may have a height 72, wherein the height 72 decreases ina direction away from the receptacle 54. The second tapered hole 52 mayhave some or all of the same features as the first tapered hole 50, andmay be symmetrical with respect to the first tapered hole 50. Asdescribed herein, the tapered channel 56 can extend in a straight linefrom the first tapered hole 50 to the second tapered hole 52.Additionally, the tapered channel 56 can intersect the axial conduit 48.As illustrated in FIG. 1A, the channel 56 of the receiving member 6 canbe configured to at least partially overlap the tapered slot 16 of thelocking member 2 when in an assembled configuration.

As illustrated in FIG. 1C, the receptacle 54 can include a longitudinalaxis that is perpendicular to, and intersects, longitudinal axis 62 ofthe axial conduit 48. The longitudinal axis of the receptacle 54 canalso be perpendicular to the tapered channel 56. In some embodiments,the receptacle 54 can include a cylindrical inner surface. Thereceptacle 54 can be configured to receive the securing element 10therein. Accordingly, the receptacle 54 may include an engagementfeature configured to engage and/or mate with the securing element 10.For example, the engagement feature can include threading or a camgroove. Advantageously, the orientation of the receptacle 54 can promotedirect access to the receptacle 54, as compared to, for example, areceptacle that may involve side-to-side insertion of the securingelement 10 (e.g., a receptacle that may be offset from and/or may notintersect with the axial conduit 48).

As illustrated in FIG. 1C, the receiving member 6 can include at leastone coupling element 70, e.g., extending from the bottom surface 65thereof. The coupling element 70 can be configured to engage a vertebralimplant. In some embodiments, the coupling element can be a projectionmember, such as a tab, as illustrated in FIG. 1C. The projection memberor tab can include a protrusion, such as a head or a hook that can beconfigured to be received within a groove or undercut in the vertebralimplant. In other embodiments, the coupling element 70 can be a grooveor slot configured to receive a portion of the vertebral implanttherein. As illustrated in FIG. 1C, the receiving member 6 can include aplurality of coupling elements 70.

In some embodiments, the receiving member 6 may optionally include aneck portion 76 extending from proximal end 60, as illustrated in FIGS.1A-C. The neck portion 76 can include a hollow cylinder (having, e.g.,constant inner and outer diameters) in fluid communication and coaxialwith the axial conduit 48. In these embodiments, the axial conduit 48may be considered to pass through both the receiving member 6 and theneck portion 76. The receiving member 6 can have an outer diameter thatis greater than an outer diameter of the neck portion 76. In someembodiments, the neck portion 76 may be configured to be received withinan implant, such as the implants described in U.S. Publication No.2011/0251691 entitled EXPANDABLE VERTEBRAL IMPLANT to McLaughlin, etal., hereby incorporated by reference herein in its entirety for allpurposes.

As illustrated in FIGS. 1A-C, the wedge member 8 can include a taperedtransverse cross section and can be configured to be received within thetapered channel 56 of the receiving member 6. The wedge member 8 can bean elongate and/or straight rod. As illustrated in FIG. 1A, the wedgemember 8 can have a generally trapezoidal (e.g., rounded trapezoidal)cross section. For example, the transverse cross section of the wedgemember 8 can have five sides connected by rounded or chamfered corners.The wedge member 8 can also have a rectangular longitudinal crosssection. In some embodiments, the wedge member 8 may be asymmetricalalong a longitudinal plane (e.g., horizontal plane 78, illustrated inFIG. 1D). For example, the wedge member 8 can include an upper wall 80and a lower wall 82, wherein the lower wall 82 is steeper than the upperwall 80. In other embodiments, the upper wall 80 can be steeper than thelower wall 82. In some embodiments, the angle of the lower wall 82,relative to horizontal plane 78, can differ from the angle of the upperwall 80 by at least 10 degrees. In other embodiments, the angle of thelower wall 82, relative to horizontal plane 78, can differ from theangle of the upper wall 80 by at least 15 degrees. In yet otherembodiments, the angle of the lower wall 82, relative to horizontalplane 78, can differ from the angle of the upper wall 80 by an amount inthe range of from about 5 degrees to about 20 degrees. As illustrated inFIG. 1D, for example, the lower wall 82 may be configured to engage thelocking member 2 and the upper wall 80 may be configured to engage thereceiving member 6. Furthermore, the wedge member 8 may be configured toapply force to both the locking member 2 and the receiving member 6.Additionally, the wedge member 8 may be configured to fit (e.g.,eccentrically or concentrically) within the tapered channel 56 of thereceiving member 6 and the tapered slot 16 of the locking member 2.

The securing element 10 can include a first end 74 and a second end 80,wherein the first end 74 is configured to contact and/or apply force tothe wedge member 8, as illustrated in FIG. 1D. The securing element 10can also include a tool-receiving recess 82 at the second end 80, asillustrated in FIG. 1C. The securing element 10 can be configured to bereceived within the receptacle 54 of the receiving member 6, asillustrated in FIG. 1A. In some embodiments, the securing element 10 canbe configured to be threaded into the receptacle 54, and can be, forexample, a set screw. In other embodiments, the securing element 10 canbe rotated into locking engagement with the receptacle 54, and can be,for example, a cam lock. As described herein, the securing element 10can advantageously be configured to stabilize an orientation (e.g., anangle) of the articulable plate member 4 relative to the receivingmember 6.

Some embodiments herein are directed to methods of installing avertebral implant assembly that can include a vertebral implant and afirst (e.g., superior or inferior) polyaxial endplate assembly, such asthe polyaxial endplate assembly 100. These methods can include providingthe first polyaxial endplate assembly 100 in an unassembled, partiallyassembled, or fully assembled state. In some embodiments where the firstpolyaxial endplate assembly 100 is partially or fully assembled, some orall of the components of the assembly 100 may be coupled or connected,but some or all of the components may still be capable of rotating,pivoting, and/or translating relative to one another.

Some embodiments can include providing the first polyaxial endplateassembly 100 in an assembled state. In these embodiments, the roundedhead portion 12 of the first locking member 2 may be disposed or nestedwithin the cavity 30 of the first articulable plate member 4, such thatneck portion 14 has passed through the aperture 32. The body portion 28of the first articulable plate member 4 may be disposed or nested withinthe variable diameter section of the first receiving member 6, and theneck portion 14 of the first locking member 2 may be disposed within theaxial conduit 48 of the first receiving member 6. The tapered slot 16 ofthe first locking member 2 may be generally aligned with the taperedchannel 56 of the first receiving member 6, and the first wedge member 8may be slideably disposed therein. The first securing element 10 may bein loose engagement with the receptacle 54 (e.g., such that the firstarticulable plate member 4 is articulable or pivotable within the firstreceiving member 6), or may not be engaged with the receptacle 54. Thoseskilled in the art may appreciate that in the assembled state, thearticulable plate member 4 may be able to articulate or pivot relativeto the locking member 2 and/or the receiving member 6.

The method can also include providing a vertebral implant that caninclude a first (e.g., superior) engagement member and/or a second(e.g., inferior) engagement member. The vertebral implant can include,for example, a corpectomy implant, an interbody implant, a vertebralbody replacement, a cage, or a spacer. In some embodiments, thevertebral implant can have a variable and/or adjustable height. In someembodiments the vertebral implant may be a vertically-expandable orextendable implant described in U.S. Publication No. 2011/0251691 toMcLaughlin et al. Those skilled in the art may appreciate that thepolyaxial endplate assemblies described herein may be used instead or inplace of the endplates described in the aforementioned publication. Oneexample of a vertebral implant is illustrated in FIG. 1E.

The superior engagement member of the vertebral implant can include acoupling element extending from a superior surface. The inferiorengagement member can include a coupling element extending from aninferior surface. With regards to either the superior and/or inferiorengagement members the coupling element may be, for example, a tab,notch and/or socket. In some embodiments, the superior and/or inferiorengagement member(s) can include a plurality of tabs. In otherembodiments, the superior and/or inferior engagement member(s) caninclude a plurality of notches.

The method can also include coupling a first (e.g., superior) polyaxialendplate assembly 100 with the first (e.g., superior) engagement member.In these embodiments, the receiving member 6 can include couplingelement 70 (e.g., tab and/or notch) extending from proximal end 60. Asdescribed herein, the receiving member 6 can include a plurality ofcoupling elements 70. The step of coupling the first polyaxial endplateassembly with the first engagement member can include engaging thecoupling element 70 of the receiving member 6 with the coupling elementof the first engagement member. For example, this step can includeinterdigitating or dovetailing the coupling element 70 of the receivingmember 6 (e.g., a tab or notch) with the coupling element of the firstengagement member (e.g., a notch or tab).

In some embodiments, the receiving member 6 can additionally include acylindrical neck portion 76. In these embodiments, the step of couplingthe first polyaxial endplate assembly with the first engagement membercan include inserting the cylindrical neck portion 76 into the socket ofthe vertebral implant, for example as illustrated in FIG. 1E.

The method can also include coupling a second (e.g., inferior) polyaxialendplate assembly with the second (e.g., inferior) engagement member.This step can be performed in substantially the same way as the couplingof the first polyaxial endplate assembly with the first engagementmember. Those skilled in the art may appreciate that in some embodimentsonly one polyaxial endplate assembly may be used (e.g., inferior orsuperior), while in other embodiments two polyaxial endplate assembliesmay be used (e.g., inferior and superior). Additionally, those skilledin the art may appreciate that steps described herein with respect tothe first polyaxial endplate assembly can also be applied toinstallation of the second polyaxial endplate assembly.

Upon assembly, the method can also include inserting the vertebralimplant assembly into a selected location, such as a cavity between twovertebral bodies created by a corpectomy or other procedure. Inembodiments using an expandable vertebral implant, this step canadditionally include expanding the vertebral implant from a first heightto a second height, e.g., until the polyaxial endplate assembly contactsthe vertebral body. Advantageously, those skilled in the art mayappreciate that the articulable plate member of the vertebral implantassembly may be configured to pivot or articulate relative to theassembly, even after being put together. Accordingly, the angles of thepolyaxial endplate assembly may be adjusted in situ to correspond to thetopography of the adjacent vertebral body.

The method can also include applying force or pressure to the firstwedge member 8. In some embodiments, the force can be applied to thefirst wedge member 8 through a first securing element 10. For example,in some embodiments the first securing element 10 can be a set screw. Inthese embodiments, the step of applying force to the first wedge member8 can include threading the set screw into the receptacle 54 of thefirst receiving member 6 until the set screw contacts the first wedgemember 8. Advantageously, those skilled in the art may appreciate thatwhen coupled together, the position (e.g., angle) of the receptacle 54of the first receiving member 6 may not be pivotable or articulable(e.g., may be fixed) relative to the overall vertebral implant assembly.Accordingly, this feature may enable the first securing element 10 toeasily be guided to the receptacle 54, as the receptacle 54 may begenerally held in place. As the set screw pushes the first wedge member8 into the tapered slot 16 and the tapered channel 56, the lower wall 82of the first wedge member 8 may apply a force (e.g., downward) to thefirst locking member 2 and the upper wall 80 may apply an opposite(e.g., upward) force to the first receiving member 6, thereby engaging,squeezing, and/or compressing the first articulable plate member 4therebetween and locking, stabilizing, and/or securing the orientation(e.g., angle) of the first articulable plate member 4 relative to thevertebral implant assembly. For example, as shown in FIG. 1A, as thewedge member 8 is driven inward, this pushes downward on the firstlocking member 2 (abutting a bottom surface of the wedge member 8) andupward on the receiving member 6 (abutting a top surface of the wedgemember 8), which thereby clamps the articulatable plate member 4 in adesired orientation. When in the locked, stabilized, and/or securedconfiguration, the first articulable plate member 4 may be effectivelyunable to pivot, articulate, and/or rotate relative to the first lockingmember 2 and/or the first receiving member 6.

Turning now to FIGS. 2A-D, polyaxial endplate assembly 200 isillustrated in accordance with embodiments described herein. Asillustrated in FIG. 2A, the polyaxial endplate assembly 200 can includean articulable plate member 202, a clamp assembly 203 comprising a firstclamp member 204, second clamp member 206, and a securing element 210,and a receiving member 208.

As illustrated in FIG. 2B, the articulable plate member 202 can includea plate portion 212 and a rounded body portion 214. The body portion 214can define a cavity 216 therein. The plate portion 212 can include anaperture 218 extending therethrough. The plate portion 212 may includean outer surface 220 having various topographical features. For example,in some embodiments the outer surface 220 of the plate portion 212 canbe planar; in other embodiments, it can be convex. In yet otherembodiments, it can be concave. Additionally, the outer surface 220 mayinclude one or more features to enhance the engagement or frictionbetween the implant and a vertebral body or other bone feature. Forexample, the outer surface 220 can be roughened, and can include, forexample, a plurality of teeth, bumps, peaks, grooves, and/or knurling.The outer surface 220 can include at least one engagement member. Theengagement member can be configured to engage and/or apply force to avertebral body. For example, the engagement member can be a spike. Insome embodiments, the outer surface 220 can include a plurality ofengagement members. The engagement member(s) can advantageously preventsliding or other translational movement of the assembly afterinstallation within the vertebral space. In other embodiments, the outersurface 220 can include an imaging member, such as one or moreradiographic markers.

The body portion 214 of the articulable plate member 202 can include aplurality of tabs 222, as illustrated in FIG. 2B. The tabs 222 can beseparated by a plurality of slots 224. The number of tabs 222 making upthe body portion 214 can vary, and can be, for example, in the range offrom about two to about twelve. In some embodiments, the tabs 222 andslots 224 may be equally sized and spaced. In other embodiments, thetabs 222 and/or slots 224 may have variable sizes. Advantageously, thebody portion 214 may be compressible, bendable, flexible, and/orconstrictable (e.g., a force may be applied to the tabs 222 which causesthe tabs 222 to flex inward, thereby reducing the volume of the cavity216).

The body portion 214 may be rounded. For example, as illustrated in FIG.2C, the body portion 214 can include an inner surface 226 and an outersurface 228, one or both of which may be curved (e.g., may include an atleast partially curved longitudinal cross section). Additionally, theouter surface 228 may include one, two, or more circumferential grooves,such as top groove 230 and bottom groove 232. The top and bottom grooves230 and 232 may have the same or different dimensions (e.g., heightand/or depth). For example, the bottom groove 232 may have a depth thatis less than that of the top groove 230. In some embodiments, the topand bottom grooves 230, 232 may be configured to engage correspondingcircumferential projections on an inner surface of a clamp member, asdescribed herein.

As illustrated in FIG. 2D, the clamp assembly 203 can include first andsecond clamp members 204, 206 and securing element 210. The first andsecond clamp members 204, 206 each can include a body having generallyC-shaped transverse cross section, and when assembled, can form a collararound the articulable plate member 202. Except as otherwise describedherein, the second clamp member 206 may share some or all of the samefeatures as the first clamp member 204. First clamp member 204, alsoreferred to herein as the front clamp member, can include an innersurface 234 and an outer surface 236. In some embodiments, the innersurface 234 may have a transverse cross section in the shape of acircular segment. In other embodiments, the inner surface 234 may have atransverse cross section in the shape of an elliptical segment. Theouter surface 236 may also have a transverse cross section in the shapeof either a circular or elliptical segment. In some embodiments, theinner surface 234 can have an elliptical transverse cross section andthe outer surface 236 can have a circular transverse cross section. Thebody of the first clamp member 204 may have a variable thickness, asmeasured between the inner and outer surfaces 234, 236. For example, asillustrated in FIG. 2A, the first clamp member 204 may have a thicknessat each end 238, 240 that is less than a thickness at the center portion242. Consequently, the thinner end portions 238, 240 may be moreflexible than the thicker center portion 242. The inner and outerdiameters of the first clamp member 204 may also vary. For example, insome embodiments, the inner diameter of the first clamp member 204 maybe less than an outer diameter of the body portion 214 of thearticulable plate member 202. However, the first clamp member 204 maystill be able to encompass the body portion 214 due to the flexibilityof the thinner end portions 238, 240. Those skilled in the art may thusappreciate that this discrepancy in diameters and/or the variablethickness of the clamp members may advantageously increase or augmentthe clamping pressure applied by the clamp assembly 203 and may promoteor enable uniform distribution of clamping pressure about thecircumference thereof.

The first and second clamp members 204, 206 may also include innerand/or outer curved longitudinal cross sections, as illustrated in FIG.2C. The inner surface 234 can be configured to engage the articulableplate member 202. Accordingly, the inner surface 234 may include one ormore features to enhance engagement between these two members. Forexample, the inner surface 234 can include a first circumferentialprotrusion or lip 239 at a bottom end of the first clamp member 204. Asillustrated in FIG. 2C, the circumferential protrusion 239 may beconfigured to engage and apply pressure to the bottom groove 232 of thearticulable plate member 202. The application of localized force nearthe bottom of the articulable plate member 202 may advantageouslyincrease the clamping strength and efficiency of the clamp assembly 203,as compared to the even distribution of force along the inner surface234. The inner surface 234 may also include a second circumferentialprotrusion or lip 241, which may be positioned near a top end of thefirst clamp member 204. The second circumferential protrusion or lip 241may also be configured to engage a groove of the articulable platemember 202, and may, for example, assist or promote alignment of thefirst clamp member 204 relative to the articulable plate member 202.

The first clamp member 204 can also include a central receptacle 243, asillustrated in FIG. 2D. A central protrusion, such as boss member 244,may also extend or protrude from the interior surface 234. The centralreceptacle 242 may pass through a body portion 246 of the first clampmember 204 and the boss member 244. As illustrated in FIG. 2D, thecentral receptacle may pass completely through from the outer surface236 of the body 246 to the inner surface 248 of the boss member 244. Thecentral receptacle 243 may be configured to receive and engage thesecuring element 210 therein. In some embodiments, the centralreceptacle 243 may include a threaded section and/or may be entirelythreaded. In some embodiments, the central receptacle 243 may have aconstant inner diameter. In other embodiments, the central receptacle243 may include an enlarged diameter portion adjacent the outer surface236 that can be configured to accommodate an enlarged head of a setscrew or other type of securing element 210.

The second clamp member 206, also referred to as the back clamp member,can also include a body 250 and a boss member 252 or other centralprotrusion through which a central receptacle 254 may pass, asillustrated in FIG. 2D. The central receptacle 254 may also beconfigured to receive and/or engage the securing element 210 therein.When in an assembled configuration, as illustrated in FIG. 2D, thoseskilled in the art may appreciate that the axes of central receptacles242, 254 may be aligned such that the securing element 210 may be firstinserted (e.g., threaded) into the first, front clamp member 204 andsubsequently into the second, back clamp member 206 in a straight line.The central receptacle 254 may include at least some of the samefeatures as the central receptacle 242. For example, the centralreceptacle 254 may be at least partially threaded. In some embodiments,the central receptacle 254 may include one or more unique features. Forexample, the central receptacle 254 may not pass entirely through thebody 250 to an outer surface of the second clamp member 206.Additionally, the central receptacle 254 may be configured to receive ashank, but not an enlarged head, of a set screw or other securingelement 210.

As described herein, the securing element 210 may be configured to bereceived within and/or engage with the central receptacles 243, 254 ofthe first and second clamp members 204, 206. In some embodiments, thesecuring element 210 may be threaded into the central receptacles 243,254, for example, when the securing element 210 is a set screw or athreaded rod. In some embodiments, the securing element 210 may be a setscrew that can include a head having a tool-receiving receptacle and athreaded shank. The head may have a diameter that is equal to or largerthan a major diameter of the threaded shank. In use, the securingelement 210 can be threaded into or otherwise engaged with the firstclamp member 204 and then into the second clamp member 206. Asillustrated in FIG. 2A, the first and second clamp members 204, 206 canbe separated by a gap 278. As the securing element 210 continues to bethreaded into the first and second clamp members 204, 206, it can pullthe first and second clamp members 204, 206 together, thereby exerting aclamping force on the articulable plate member 202. Thus, the securingelement 210 can advantageously be used to stabilize an orientation(e.g., an angle) of the articulable plate member 202 relative to thereceiving member 208.

As illustrated in FIG. 2B, the receiving member 208 can include arounded portion 266 having a convex exterior surface 256 and a roundedor curved longitudinal cross section. The receiving member 208 can alsoinclude a cylindrical portion 268 extending proximally therefrom. Thereceiving member 208 may be generally annular or hollow and can includea passageway 258 extending axially from a distal end surface 260 to aproximal end surface 262. The rounded portion 266 can include anaxially-variable thickness, as measured between outer surface 256 andinner surface 270. The cylindrical portion 268 can have a constantthickness. At least a portion of the receiving member 208 may beconfigured to be received within the cavity 216 of the body portion 214of the articulable plate member 202, and at least a portion of theexterior surface 256 may be configured to contact or engage the innersurface 226 of the body portion 214. In some embodiments, the roundedportion 266 of the receiving member 208 can additionally include a ledge272 extending along and/or protruding from at least a portion of theinterior surface 270. The distal end surface 260 can also include atleast one axial pocket or slot 274, as illustrated in FIG. 2A. Asillustrated in FIGS. 2A-B, the receiving member 208 can include twoslots 274, 276. As illustrated in FIG. 2A, the two slots may be orientedapproximately 180 degrees apart from each other. The two slots 274, 276may be configured to receive the boss members 244, 252 of the first andsecond clamp members 204, 206 therein. Advantageously, the slots 274,276 may entrap, constrain, or restrain the boss members 244, 252 andreduce spinning or rotating of the clamp assembly 203 relative to thereceiving member 208.

In some embodiments, the receiving member 208 can include one or morecoupling elements 264. The coupling element 264 can be configured tocouple or engage the polyaxial endplate assembly 200 with a vertebralimplant, such as those described in U.S. Publication No. 2011/0251691 toMcLaughlin et al. As illustrated in FIG. 2B, in some embodiments, thecoupling element 264 can include a projection member, such as a tab,extending from the proximal end surface 262. As further illustrated inFIG. 2B, the projection member or tab can include a protrusion, such asa head or a hook that can be configured to be received within a grooveor undercut in the vertebral implant. In other embodiments, the couplingelement 264 can be a groove or slot configured to receive a portion ofthe vertebral implant therein. As illustrated in FIG. 2B, the receivingmember 208 can include a plurality of coupling elements 264.

In some embodiments, the receiving member 208 may optionally include aneck portion (not shown) which can extend from the proximal end 262. Theneck portion can include a hollow cylinder (having e.g., constant innerand outer diameters) in fluid communication and coaxial with thepassageway 258. The receiving member 208 can have an outer diameter thatis greater than an outer diameter of the neck portion. In someembodiments, the neck portion may be configured to be received within avertebral implant as part of the coupling process.

Some embodiments herein are directed to methods of installing avertebral implant assembly that can include a vertebral implant and afirst (e.g., superior or inferior) polyaxial assembly, such as thepolyaxial endplate assembly 200. These methods can include providing thefirst polyaxial endplate assembly 200 in an unassembled, partiallyassembled, or fully assembled state. In some embodiments where the firstpolyaxial endplate assembly 200 is partially or fully assembled, some orall of the components of the assembly 200 may be coupled or connected,but some or all of the components may still be capable of rotating,pivoting, and/or translating relative to one another.

Some embodiments can include providing the first polyaxial endplate 200in an assembled state. In these embodiments, the rounded portion 266 ofthe receiving member 208 may be at least partially disposed or nestedwithin the cavity 216 of the articulable plate member 202, for example,by snapping the articulable plate member 202 over the receiving member208. The clamp assembly 203 may be engaged with the body portion 214 ofthe articulable plate member 202, for example, by positioning the firstand second clamp members 204, 206 around the articulable plate member202 and inserting the securing member 210 therethrough via centralreceptacle 243. The step of positioning the first and second clampmembers 204, 206 around the articulable plate member 202 may furtherinclude inserting the boss members 244, 252 into the slots 274, 276 onthe receiving member 208. Those skilled in the art may appreciate thatin the assembled state, the articulable plate member 202 may be able toarticulate or pivot relative to the receiving member 208 and/or thelocking assembly 203.

The method can also include providing a vertebral implant that caninclude a first (e.g., superior) engagement member and/or a second(e.g., inferior) engagement member. The vertebral implant can be, forexample, a corpectomy implant, an interbody implant, a vertebral bodyreplacement, a cage, or a spacer. In some embodiments, the vertebralimplant can have a variable and/or adjustable height. In someembodiments the vertebral implant may be a vertically-expandable orextendable implant described in U.S. Publication No. 2011/0251691 toMcLaughlin et al. Those skilled in the art may appreciate that thepolyaxial endplate assemblies described herein may be used instead ofthe endplates described in the aforementioned publication.

The superior engagement member of the vertebral implant can include acoupling element extending from a superior surface. The inferiorengagement member can include a coupling element extending from aninferior surface. With regards to either the superior and/or inferiorengagement members the coupling element may be, for example, a tab,notch and/or socket. In some embodiments, the superior and/or inferiorengagement member(s) can include a plurality of tabs. In otherembodiments, the superior and/or inferior engagement member(s) caninclude a plurality of notches.

The method can also include coupling a first (e.g., superior) polyaxialendplate assembly 200 with the first (e.g., superior) engagement member.In these embodiments, the receiving member 208 can include couplingelement 264 (e.g., tab and/or notch) extending from proximal end 262. Asdescribed herein, the receiving member 208 can include a plurality ofcoupling elements 264. The step of coupling the first polyaxial endplateassembly with the first engagement member can include engaging thecoupling element 264 of the receiving member 208 with the couplingelement of the first engagement member. For example, this step caninclude interdigitating or dovetailing the coupling element 264 of thereceiving member 208 (e.g., a tab or notch) with the coupling element ofthe first engagement member (e.g., a notch or tab). In some embodiments,the coupling element 264 can be a projection member that includes aprotrusion, and the first engagement member can be an undercut in thevertebral implant. In these embodiments, the coupling step can includesnapping the protrusion into the undercut, for example by applyingpressure to momentarily deflect, flex, or bend the coupling element 264outwards and allowing the protrusion to be received within the undercutwhen the coupling element 264 returns to a neutral position.

In some embodiments, the receiving member 208 can additionally include acylindrical neck portion. In these embodiments, the step of coupling thefirst polyaxial endplate assembly with the first engagement member caninclude inserting the cylindrical neck portion into the socket of thevertebral implant.

The method can also include coupling a second (e.g., inferior) polyaxialendplate assembly with the second (e.g., inferior) engagement member.This step can be performed in substantially the same way as the couplingof the first polyaxial endplate assembly with the first engagementmember. Those skilled in the art may appreciate that in some embodimentsonly one polyaxial endplate assembly may be used (e.g., inferior orsuperior), while in other embodiments two polyaxial endplate assembliesmay be used (e.g., inferior and superior). Additionally, those skilledin the art may appreciate that steps described herein with respect tothe first polyaxial endplate assembly can also be applied toinstallation of the second polyaxial endplate assembly.

Upon assembly, the method can also include inserting the vertebralimplant assembly into a selected location, such as a cavity between twovertebral bodies created by a corpectomy or other procedure. Inembodiments using an expandable vertebral implant, this step canadditionally include expanding the vertebral implant from a first heightto a second height, e.g., until the polyaxial endplate assembly contactsthe vertebral body. Advantageously, those skilled in the art mayappreciate that the articulable plate member of the vertebral implantassembly may be configured to pivot or articulate relative to theassembly, even after being put together. Accordingly, the angles of thepolyaxial endplate assembly may be adjusted in situ to correspond to thetopography of the adjacent vertebral body.

The method can also include applying a force to the first articulableplate member 202 to stabilize an orientation of the first articulableplate member 202 relative to the vertebral implant. This step caninclude constricting and/or compressing the first and second clampmembers 204, 206 around the body portion 214 of the first articulableplate member 202. The first and second clamp members 204, 206 may beconstricted by engaging the securing element 210 therewith. As describedherein, in embodiments where the securing element 210 is a set screw andthe first and second clamp members 204, 206 include threaded centralreceptacles, as the set screw is threaded into the central receptacles243, 254, the set screw may effectively compress or pull the first andsecond clamp members 204, 206 together. Those skilled in the art mayappreciate that when the body portion 214 is constricted, squeezed,and/or compressed, the tabs 222 may flex inward in enhanced frictionalengagement with the receiving member 208, thereby locking, stabilizing,and/or securing the orientation (e.g., angle) of the first articulableplate member 202 relative to the vertebral implant assembly. When in thelocked, stabilized, and/or secured configuration, the first articulableplate member 202 may be effectively unable to pivot, articulate, and/orrotate relative to the first clamping assembly 203 and/or the firstreceiving member 208.

As described herein, polyaxial endplate assemblies may advantageously beused in combination with vertebral implants to enable or promote acustomized, adjustable fit between vertebral bodies. Regardless, in use,a vertebral implant assembly kit may include a number of interchangeableendplate assemblies and vertebral implants having varyingcharacteristics (e.g., height, endplate dimensions, and angulation)configured to fit a wide variety of individuals. To select theappropriate combination of endplate assemblies and vertebral body, asurgeon or other practitioner may measure various parameters of theintervertebral space. This may be done intraoperatively using a physicalmeasurement tool, such as a ruler or caliper, and/or preoperativelyusing software in combination with imaging techniques such as x-ray, CTor MRI. In some instances, different methods may be used to measuredifferent characteristics. For example, height and footprint (e.g.,width) may be measured physically and angulation may be measured usingimaging. In addition to being potentially time-consuming, there may beissues with these methods that limit their accuracy. For example, heightof the intervertebral space can be difficult to measure physically, ascaliper devices may not fit within the operative area or may beobstructed by nearby anatomy, and generally may not be the same shape asthe vertebral implant assembly. Additionally, caliper devices may not beable to exert force sufficient to restore height and/or alignment tocollapsed spinal segments, and may therefore not be able torealistically measure the appropriate dimensions for the vertebralimplant assembly. Imaging can also have limitations. For example,preoperative images of the spine may not reflect the actual dimensionsneeded for a vertebral implant assembly. Accordingly, described hereinare vertebral endplate trial devices that can measure footprint,angulation, and height all in one step, thus saving time over othermethods that may require multiple measurement techniques. As describedfurther herein, the endplate trials may be configured to exert force onthe vertebral bodies and/or restore height to collapsed segments, andmay therefore provide a more accurate determination of the appropriatedimensions for the vertebral implant assembly. Once inserted, x-rays orother images may be taken in situ to confirm fit.

Turning now to FIGS. 3A-10, endplate trials are illustrated inaccordance with embodiments described herein. The endplate trial caninclude a top surface, a bottom surface, and a side surfacetherebetween. Those skilled in the art may appreciate that thedirectional terms used herein, such as “top,” “bottom,” “side,” “front,”“back,” and the like are used for descriptive purposes and do notnecessarily limit the orientation(s) in which the endplate trials may beused. For example, the endplate trials described herein may beconfigured to engage either a superior or inferior vertebral surface.Additionally, the endplate trial can include a coupling elementconfigured to reversibly engage a vertebral implant device (e.g., adevice for use in a vertebral implant procedure). Any suitable vertebralimplant device may be used. For example, the vertebral implant devicemay be a vertebral trial, such as those described in U.S. PublicationNo. 2012/0232660 to Davenport, entitled EXPANDABLE TRIAL ASSEMBLY FOREXPANDABLE VERTEBRAL IMPLANT, which is hereby incorporated by referenceherein in its entirety. In other embodiments, the vertebral implantdevice may be a vertebral prosthesis, such as, without limitation, acage, spacer, vertebral body replacement, interbody implant, orexpandable vertebral implant as described in U.S. Publication No.2011/0251691 and/or U.S. Publication No. 2012/0232660.

FIGS. 3A-F illustrate endplate trial 300. As illustrated in FIG. 3A,endplate trial 300 can include a top surface 302, bottom surface 304,and side surface 306 therebetween. Endplate trial 300 may also include achamfered edge 308 between the side surface 306 and the top and/orbottom surfaces 302, 304. The top surface 302 may be configured toengage (e.g., contact and/or apply force to) a vertebral body. Forexample, the top surface 302 may have a curvature, as viewed from theside surface, selected from convex, concave, and planar. The bottomsurface 304 may also have a curvature, as viewed from the side surface,selected from convex, concave, and planar. Additionally, endplate trial300 may have a height, as measured between the top surface 302 andbottom surface 304, which varies along a length or width thereof. Theshape of the endplate trial 300, as viewed from the top and/or bottomsurface 302, 304, may also vary. For example, the endplate trial 300 mayhave a shape selected from circular, elliptical, square, trapezoidal,rectangular, and kidney-shaped.

As described herein, the endplate trial may advantageously include acoupling element configured to reversibly engage the endplate trial witha vertebral implant device. In some embodiments, the coupling elementmay be configured to slideably receive at least a portion of thevertebral implant device therein. For example, the coupling element maybe an undercut, such as lateral undercut 310, as illustrated in FIG. 3A.

As illustrated in FIG. 3B, the lateral undercut 310 can include a firstor front opening 312 on the side surface 306 of the endplate trial 300.The front opening 312 may be located at a first or front end 314 of theendplate trial 300 and may have a width greater than a width of theportion of the vertebral implant device to be received within thelateral undercut 310. The lateral undercut 310 may further include asecond or back opening 316 on the side surface 306 at a second or backend 318 of the endplate trial 300. Thus, in some embodiments, thelateral undercut 310 may pass entirely through the endplate trial 300from one section of the side surface 306 to another section of the sidesurface 306. In other embodiments, the lateral undercut 310 may passonly partially through the endplate trial 300. Additionally, the lateralundercut 310 may define an inner surface 324 of the endplate trial. Thesecond or back opening 316 may have a width that is less than the widthof the portion of the vertebral implant device to be received within thelateral undercut 310. The lateral undercut 310 can additionally includea rounded cavity 320 between the front opening 312 and the back opening316. The rounded cavity 320 may have a diameter that is greater than thewidth of the back opening 316. The lateral undercut 310 may also includea transition area 322 between the rounded cavity 320 and the frontopening 312. The transition area 322 may advantageously be configured tohave a width that is less than a width of the portion of the vertebralimplant device to be received within the lateral undercut 310.Conversely, the transition area 322 may define first and secondprotrusions 338, 340 on inner side walls 342, 344 of the endplate trial300, as illustrated in FIG. 3B.

The endplate trial may additionally include a retaining element. Theretaining element may be configured to retain the portion of thevertebral implant device in engagement with the coupling element (e.g.,within the rounded cavity 320). In some embodiments, the retainingelement may include a spring element. The spring element may includefirst and second deflectable members, wherein each deflectable memberincludes a protrusion configured to engage the vertebral implant device.As illustrated in FIG. 3C, in some embodiments the retaining element mayinclude a vertical slot 326. As illustrated in FIGS. 3B-C, the verticalslot 326 may be in fluid communication with, overlap, and/or extendparallel to the lateral undercut 310. The vertical slot 326 can have adepth that extends entirely through the endplate trial from the topsurface 302 to the bottom surface 304. The vertical slot 326 may alsohave a first end that includes an opening 328, a second end thatincludes a rounded terminus 330, and an elongate void 332 therebetween.As illustrated in FIG. 3C, the opening 328 may be located adjacent thefront end 314 of the endplate trial 300 and may pass through the sidesurface 306.

As illustrated in FIG. 3C, the vertical slot 326 may divide the endplatetrial 300 into first and second deflectable sections 334, 336. The firstand second deflectable sections 334, 336 may be flexibly connected,e.g., may be configured to bend, flex, deflect, and/or pivot relative toeach other. The vertical slot 326 may have a width as defined by thedistance between the first and second deflectable sections 334, 336. Asillustrated in FIG. 3C, the width of the vertical slot 326 may vary, andin some embodiments the vertical slot 326 can include a constant widthsection (e.g., corresponding to the elongate void 332) and a variablewidth section (e.g., corresponding to the rounded terminus 330).Additionally, the maximum width or diameter of the rounded terminus 330may be greater than the width of the elongate void 332. Advantageously,the relatively wide rounded terminus 330 may contribute to the springmechanism of the endplate trial 300 by encouraging and/or promoting thefirst and second deflectable sections 334, 336 to bend or deflect,and/or by enhancing their range of motion.

In use, the endplate trial 300 may be configured to be engaged orcoupled with a tip of an implant trial assembly, for example, implanttrial assembly 356 illustrated in FIG. 3D. Implant trial assembly 356can include an expandable tip assembly 358 that includes a generallydisc-shaped endplate 360. In these embodiments, the disc 360 of theimplant trial assembly tip 358 may be laterally inserted (e.g., slid)into the lateral undercut 310. As the widest part of the disc 360 entersthe narrow transition area 332, the disc 360 contacts the protrusions338, 340 and causes the first and second deflectable sections 334, 336to deflect or splay outwards. As the first and second deflectablesections 334, 336 splay apart, the width of the transition area 322temporarily expands, thereby allowing the disc 360 to pass through tothe rounded cavity 320. Once pressure is released from the protrusions338, 340, the deflectable sections 334, 336 return or spring back totheir neutral orientation, thereby trapping or retaining the disc 360within the rounded cavity 320, as illustrated in FIG. 3E.

The bottom surface 304 of the endplate trial 300 is illustrated, forexample, in FIG. 3C. As illustrated therein, the bottom surface 304 maybe divided into first and second sections 343, 345 separated by a gap346. The gap 346 may include one or more straight (e.g., linear)sections and one or more curved sections. Conversely, the first andsecond bottom sections 343, 345 may each include a curved or partiallycircular cutout 348, 350. The cutouts 348, 350 may be configured toreceive a portion of the vertebral implant device therein (e.g.,cylindrical body 364 of expandable trial assembly 356, as illustrated inFIG. 3D).

In some embodiments, the endplate trial may also include one or morestabilizing members. The stabilizing member may be configured to engageat least a portion of the vertebral implant device, for example, onlywhen the device is in a particular configuration. For instance, theexpandable tip assembly 358 of expandable trial assembly 356,illustrated in FIG. 3D, may be configured to transition reversiblybetween an expanded configuration and a contracted configuration. Inthese embodiments, the stabilizing member may be configured to engage atleast a portion of the expandable tip assembly 358 when the expandabletrial assembly 356 is in the contracted configuration. Advantageously,in providing additional engagement between the endplate trial and thevertebral implant device, the stabilizing member may inhibit theinadvertent removal or release of the endplate trial from the vertebralimplant device. In some embodiments, the stabilizing member may includeone or more protrusions or projections on a bottom surface of theendplate trial. As illustrated in FIG. 3C, the first and second bottomsections 343, 345 of the endplate trial 300 may each include aprojection 352, 354 extending therefrom. The projection(s) may have avariety of shapes, such as round, circular, square, rectangular,pentagonal, and annular, and may include rounded corners and/or edges.As illustrated in FIG. 3C, the projections 352, 354 may each take theshape of a circular or curved ring segment. Together, the projections352, 354 may form a partial circle or oval. The width or diameter of thepartial circle or oval may vary depending on the dimensions of thevertebral implant device with which the endplate trial 300 may beengaged. In some embodiments, the partial circle or oval may beconfigured to at least partially surround a portion of expandable trialassembly 356, as illustrated in FIG. 3F. For example, the circular ringsegments 352, 354 may be spaced apart by a maximum distance that isgreater than a diameter of a gear member 362 of the expandable trialassembly 356.

Turning to FIG. 4A-D, endplate trial 400 is illustrated in accordancewith embodiments described herein. Unless otherwise described herein,endplate trial 400 may include some or all of the same features asdescribed with respect to endplate trial 300. As illustrated in FIG. 4A,endplate trial 400 may include a top surface 402, bottom surface 404,and side surface 406 therebetween. Endplate trial 400 may also include acoupling element configured to reversibly engage at least a portion of avertebral implant device (e.g., expandable trial assembly 356). Thecoupling element of endplate trial 400 may include a lateral undercut410. The lateral undercut 410 may pass partially or completely throughthe endplate trial 400 (e.g., between a front end 414 and a back end416, illustrated in FIG. 4B). For example, as illustrated in FIG. 4B,the lateral undercut 410 may include a first or front opening 418 and arounded cavity 420. Additionally, lateral undercut 410 may define aninner surface 412 of the endplate trial 400. In some embodiments, theendplate trial 400 can further include a groove 411 on the inner surface412 that can extend along a length of the lateral undercut 410, asillustrated in FIGS. 4A-B. The groove 411 may advantageously encouragesliding of the vertebral implant device within the lateral undercut 410.

Endplate trial 400 may additionally include a retaining element. Asillustrated in FIG. 4B, the retaining element can include a first orleft vertical slot 422 and a second or right vertical slot 424. Each ofthese vertical slots may extend entirely through the endplate trial 400from the top surface 402 to the bottom surface 404. As illustrated inFIG. 4B, each of the vertical slots 422, 424 may be generally U-shapedas viewed from the top and bottom surfaces 402, 404 and may define firstand second (e.g., left and right) deflectable arms 426, 428. The firstand second deflectable arms 426, 428 may each include a protrusion orprong 430, 432 that protrudes into the lateral undercut 410.

In use, the endplate trial 404 may be configured to be engaged orcoupled with a tip of an implant trial assembly, for example, implanttrial assembly 356 illustrated in FIG. 4D. As described herein, implanttrial assembly 356 can include an expandable tip assembly 358 thatincludes a generally disc-shaped endplate 360. In these embodiments, thedisc 360 may be laterally inserted (e.g., slid) into the lateralundercut 410. As the widest part of the disc 360 contacts or appliesforce to the protrusions 430, 432, it causes first and seconddeflectable arms 426, 428 to deflect or splay outwards. As the first andsecond deflectable arms 426, 428 splay apart, the width of the lateralundercut 410 temporarily expands, thereby allowing the disc 360 to passthrough to the rounded cavity 420. Once pressure is released from theprotrusions 430, 432, the deflectable arms 426, 428 may return or springback to their neutral position, thereby trapping or retaining the disc360 within the rounded cavity 420, as illustrated in FIGS. 4B and 4D.

The bottom surface 404 of the endplate trial 400 is illustrated in FIG.4C. Bottom surface 404 may include a curved cutout 434. The curvedcutout 434 may include an opening 436, a linear passageway 438, and arounded terminus 440. The rounded terminus 440 may be coaxial with therounded cavity 420. The curved cutout 434 may be configured toaccommodate a portion of the vertebral implant device (e.g., cylindricalbody 364, illustrated in FIG. 4D) therein.

Endplate trial 400 may include one or more stabilizing members. Asillustrated in FIGS. 4C-D, the stabilizing members may include first andsecond projections 442, 444 extending from the bottom surface 404. Theprojections 442, 444 may have a five-sided shape (e.g., pentagonal). Theprojections 442, 444 may be spaced apart by a distance that can varydepending on the dimensions of the vertebral implant device with whichthe endplate trial 400 may be engaged. As described herein, and asillustrated in FIG. 4D, expandable trial assembly 356 may includeexpandable tip assembly 358 that includes, among other things, a gearmember 362. The first and second projections 442, 444 may be configuredto engage the gear member 362 when the expandable tip assembly 358 is inthe contracted configuration. Thus, in some embodiments, the projections442, 444 may be spaced apart by a distance that is less than a diameterof the gear member 362, as illustrated in FIG. 4D. However, in order toallow the cylindrical body 364 to pass freely along the cutout 434, theprojections 442, 444 may also be spaced apart by a distance that isgreater than a diameter of the cylindrical body 364.

Those skilled in the art may appreciate that the endplate trialsdescribed herein may include other coupling mechanisms or elements forreversibly coupling with a vertebral implant device having variousproperties. Examples of alternative coupling elements are illustrated inFIGS. 5-10. Those skilled in the art may appreciate that the features ofthe endplate trials illustrated in FIGS. 5-10 may be combined with eachother as well as with one or more features of endplate trials 300 and400 described herein.

In some embodiments, the vertebral implant device may include a hollowreceptacle (e.g., a hollow cylinder), and the endplate trial may includea coupling element that is configured to be received within the hollowreceptacle. As illustrated in FIGS. 5-6, the endplate trial 500, 600 mayinclude a plurality of deflectable arms 502, 602 extending from a bottomsurface 504, 604 thereof. Each arm 502, 602 may include a protrusion506, 606 that may be configured to engage or press against an innersurface of the hollow receptacle. In some embodiments, the hollowreceptacle may further include a groove or depression configured toreceive the protrusion 506, 606. The arm(s) 502 of endplate trial 500may be configured to engage the hollow receptacle in a snap fit. Forexample, the arm(s) 502 may be squeezed into the hollow receptacle, andreleased once the protrusion(s) 506 are positioned at the groove. Asillustrated in FIG. 6, the endplate trial 600 may further include athreaded passageway 608 and a fastener or screw member 610. In use, thescrew member 610 may be advanced through the threaded passageway 608 topush or splay the arms 602 apart, thereby engaging the protrusion 606with the inner surface of the hollow receptacle.

In other embodiments, the vertebral implant device may include athreaded extension member. Accordingly, FIG. 7 illustrates endplatetrial 700 which includes an internally-threaded cavity 702 that mayextend through a bottom surface 704 thereof. The internally-threadedcavity 702 may be configured to threadably engage (e.g., thread onto)the vertebral implant device. FIG. 8 illustrates another embodiment,endplate trial assembly 800, which includes an endplate trial 802 and acollar 804. The collar 804 can include an internally-threaded cavity andcan be configured to threadably engage (e.g., thread onto) the vertebralimplant device, as well as being configured to engage the endplate trial802. The collar 804 may also include a groove or undercut 806 configuredto receive a portion of the endplate trial 802, such as a lip 808. Theendplate 802 may be configured to slide or snap onto the collar 804.This type of endplate trial design may be advantageous when endplatetrial 802 is non-circular, as the endplate trial 802 may not be threadeddirectly onto the vertebral implant device.

In some embodiments, the vertebral implant device may include a solidextension member, as illustrated in FIGS. 9-10. As illustrated in FIG.9, the solid extension member may further include an undercut. In theseembodiments, endplate trial 900 may include one or more arms 902extending from a bottom surface 904. Each arm 902 may further include aprotrusion 906. The arms 902 may be configured to engage an outersurface of the solid extension member, for example, in a snap fit. Inuse, the endplate trial 900 may be snapped or pushed onto the vertebralimplant device. The arms 902 may temporarily splay or spring outwards,and upon return to a neutral position, the protrusion 906 may beretained within the undercut of the solid extension member.

FIG. 10 illustrates endplate trial 1000 which can include a couplingelement which includes a cavity 1002. The cavity 1002 can be configuredto receive at least a portion of the vertebral implant device therein.Endplate trial 1000 can further include a retaining element thatincludes a passageway 1004 that extends from a side surface to thecavity and that is configured to receive a fastener 1006 therein. Thefastener 1006 may include, for example, a ball plunger, a springplunger, or a screw. In use, the endplate trial 1000 may be configuredlike a set screw collar, wherein the fastener 1006 may be threaded intothe passageway 1004 until it contacts and engages the vertebral implantdevice in a friction fit.

Embodiments herein are also directed to methods of inserting a vertebralimplant. In some embodiments, the method can include providing avertebral trial, such as expandable trial assembly 356, and at least oneendplate trial as described herein, such as endplate trial 300 orendplate trial 400. The expandable trial assembly 356 may be provided,for example, in a partially contracted configuration. The method canfurther include coupling the endplate trial with the vertebral trial,for example, by sliding a portion of the vertebral trial (e.g., disc360) laterally into an undercut on the endplate trial and retaining thedisc 360 within a rounded cavity thereof. The method can further includepositioning the overall assembly (e.g., expandable trial assemblycoupled to at least one trial endplate) between two vertebrae, forexample, as part of a corpectomy procedure. The expandable tip assembly358 of the expandable trial assembly 356 may then be expanded, forexample, by causing the gear member 362 to rotate. The expandable tipassembly 358 may be expanded until the top surface of the endplate trialcontacts a vertebral body and/or the desired spinal alignment isattained. The method can further include measuring expansion of theoverall assembly, for example, with a scale at a proximal end of theexpandable trial assembly 356. As described herein, the endplate trialscan advantageously enable or promote measurement of footprint,angulation, and height in one step or procedure. Once measurements aretaken, the overall assembly may be removed from the vertebral space.This step may then include contracting or retracting the overallassembly. As described herein, when in a contracted configuration, theprotrusions on the bottom surface of the endplate trial may engage aportion of the expandable tip assembly (e.g., gear member 362), therebyproviding enhanced stability and reducing the likelihood that theendplate trial unintentionally uncouples from the expandable trialassembly 356 during the removal step. Those skilled in the art mayappreciate that if one or more parameters of the particular endplatetrial is unacceptable, the endplate trial may be uncoupled or removedfrom the expandable trial assembly 356 and exchanged for a differentendplate trial. Thus, the readily interchangeable nature of the endplatetrials described herein may enable a surgeon to easily try out variousendplate trials and quickly obtain the appropriate measurements. Oncethe proper measurements are obtained, an implant (e.g., an expandableimplant, optionally including one or more polyaxial endplate assembliesdescribed herein) may be selected on the basis of these measurements.Thereafter, the method can further include positioning the selectedimplant between the vertebrae and expanding the implant based on themeasured expansion of the expandable trial assembly 356.

FIG. 11A illustrates a view of an alternative expandable vertebralimplant in accordance with some embodiments. In some embodiments, theexpandable vertebral implant 1000 can comprise an interbody spacer, suchas a corpectomy device including a polyaxial endplate assembly. Thepolyaxial endplate assembly, which includes an endplate 1020 capable ofpolyaxial adjustability, a receptacle for receiving the endplate 1020therein, and a securing element 1010 for locking the angular position ofthe endplate 1020, advantageously accommodates natural kyphosis orlordosis of a patient. As opposed to different interbody spacers, whichdo not have angulating or polyaxial endplates and thus require a surgeonto guess on the type of endplate that should conform to a patient'sendplate, the polyaxial endplate assembly provided herein eliminates theguesswork and eases the insertion of the implant 1000 into the patient.

The expandable vertebral implant 1000 comprises an interbody spacer suchas a corpectomy device capable of expanding across one or more vertebrallevels. The expandable vertebral implant 1000 comprises an upperendplate 1020 and a lower endplate 1062 that are capable of expandingaway from one another to engage respective upper and lower vertebralendplates. In the present embodiment, the lower endplate 1062 isnon-polyaxial, while the upper endplate 1020 is part of a polyaxialendplate assembly and capable of different angulations. In otherembodiments, the lower endplate 1062 can be part of a polyaxial endplateassembly while the upper endplate 1020 can be non-polyaxial. In yetother embodiments, both the upper endplate 1020 and the lower endplate1062 can be part of polyaxial endplate assemblies. These endplates 1020,1062 will be discussed further below.

To expand the distance of separation between the upper endplate 1020 andthe lower endplate 1062, the implant 1000 includes an inner member 1012,an outer member 1014 and a gear member 1016. Each of these components isakin to the similarly named components in FIG. 2 of U.S. 2011/0251691 toMcLaughlin (incorporated by reference in its entirety), and operate in asimilar manner. The upper endplate 1020 is attached to the inner member1012 via coupling elements 1070 (shown in FIGS. 11A and 14A-14D), whilethe lower endplate 1062 is attached to the outer member 1014 via similarcoupling elements 1060. In particular, as the gear member 1016 isrotated, this causes the inner member 1012 to thread and rotateupwardly, thereby causing the upper endplate 1020 to expand away fromthe lower endplate 1062. The upper endplate 1020 can expand until itfirmly contacts an upper vertebral endplate of a patient. Upon contactwith the upper vertebral endplate, the upper endplate 1020 can adjustpolyaxially to match the natural anatomy of the patient until it issecurely locked in a desired angulated position.

The outer member 1014 comprises one or more mounting features or slots1052, and a threaded opening 1054. The slots 1052 and the threadedopening 1054 are capable of being engaged by an expansion tool includinga gear attached thereon (shown for example in FIG. 8 of incorporate U.S.2011/0251691). The tool gear is capable of engaging the gear member 1016via its gear teeth 1074, thereby causing rotation of the gear member1016. In some embodiments, the outer member 1014 is formed of a polymer,such as PEEK.

The inner member 1012 comprises outer threads that extend along itslongitudinal axis. As the gear member 1016 is rotated by the expansiontool, inner threads of the gear member 1016 engage the outer threads ofthe inner member 1012, thereby causing the inner member 1012 to threadand move upwardly. In some embodiments, the inner member 1012 is formedof a polymer, such as PEEK.

The outer member 1014 is attached to a bottom endplate 1062. In thepresent embodiment, the bottom endplate 1062 is non-polyaxial and has afixed angle. In other embodiments, the bottom endplate 1062 can be partof a polyaxial assembly. The bottom endplate 1062 comprises one or moreprotrusions, engagement members, teeth or spikes 1096 for initiallyengaging a lower vertebral endplate. In addition, the bottom endplate1062 comprises one or more protrusions, engagement members, teeth orspikes 1097 that are shorter, but higher in number, than the spikes1096. In addition, the bottom endplate 1062 includes one or more reliefspaces or slots 1064 that are configured to engage and connect with tabs1060 of the outer member 1014, thereby connecting the two componentstogether. In some embodiments, the bottom endplate 1062 is formed of ametal or metal alloy, such as titanium.

The inner member 1012 is attached to a polyaxial endplate assembly. Inthe present embodiment, the polyaxial endplate assembly comprises anupper endplate 1020, a receptacle 1054 for receiving the upper endplate1020, and a securing element 1010. The upper endplate 1020 comprises anupper portion and a lower portion. The upper portion of the upperendplate 1020 comprises one or more protrusions, engagement members,teeth or spikes 1096 for initially engaging an upper vertebral endplate.In addition, the upper endplate 1020 comprises one or more protrusions,engagement members, teeth or spikes 1097 that are shorter, but higher innumber, than the spikes 1096. The lower portion of the upper endplate1020 comprises a downwardly extending extension portion 1091 havinggeared or splined features 1093. The splined features 1093advantageously provide torsional stability to the upper endplate 1020,which is received in the receptacle 1054. In addition, the upperendplate 1020 includes an arched clearance region 1021, whichaccommodates and provides clearance for the flanged portion 1055 of thereceptacle 1054, discussed further below. In some embodiments, the upperendplate 1020 is formed of a metal or metal alloy, such as titanium.

The receptacle 1054 (shown best in FIG. 11B) comprises an upper portionand a lower portion. The upper portion of the receptacle 1054 comprisesan annular body attached to a flanged portion 1055. The flanged portion1055 includes a tool receiving recess 1082 formed therethrough, which isconfigured to receive a securing element 1010 therein. The securingelement 1010 (also shown in FIG. 11B) comprises a head portion 1088 anda threaded shaft portion 1089. The threaded shaft portion 1089 isdesigned to engage with clamping nut 1077 (also shown in FIG. 11B) toform a locking system that secures the upper endplate 1020 in a desiredangular position or orientation. As the securing element 1010 isthreaded into the clamping nut 1077, a clamp is formed between the twomembers with the upper endplate 1020 compressed therebetween (as shownin FIG. 13), thereby securing the upper endplate 1020 in the desiredangular position or orientation. The lower portion of the receptacle1054 comprises a stem or neck portion 1076 configured to extend throughthe inner member 1012. In addition, the receptacle 1054 furthercomprises coupling elements 1070 in the form of tabs designed tointerdigitate with tabs 1038 of the inner member 1012, thereby securingthe receptacle to the inner member 1012.

In some embodiments, the expandable vertebral implant 1000 operates asfollows. After one or more intervertebral discs and optionally, one ormore vertebrae, are removed, the implant 1000 can be inserted into thecavity. Spikes 1096 on the lower endplate 1062 of the implant 1000 canengage a lower vertebral endplate. With the implant 1000 in the cavity,an expansion tool having a gear can engage and rotate the gear member1016, which causes the inner member 1012 to expand upwardly away fromthe outer member 1014 of the implant 1000, thereby causing the upperendplate 1020 to separate away from the lower endplate 1062. As theupper endplate 1020 expands upwardly, it contacts an upper vertebralendplate. The upper endplate 1020 is capable of polyaxial movement andwill advantageously conform to the natural anatomy of the spine,including any kyphosis or lordosis in the patient. Once the upperendplate 1020 has conformed to the natural anatomy, the securing element1010 can be actuated and rotated, thereby locking the upper endplate1020 in a desired angular position. The expandable vertebral implant1000 can thus serve as a corpectomy device that promotes fusion acrossone or more levels of the spine.

FIG. 11B illustrates an exploded view of the alternative expandablevertebral implant of FIG. 11A. The exploded view shows componentsdiscussed above including the inner member 1012, the outer member 1014,the gear member 1016, the upper endplate 1020, and the lower endplate1062. Additional features, including the locking system comprising thesecuring element 1010 and the clamping nut 1077, as well as the lockring 1081 and locking member 1080, which were not as easily visible inFIG. 11A, are clearly shown. These additional features are discussedbelow.

The exploded view in FIG. 11B shows the various components of thelocking system that will secure the upper endplate 1020 in a desiredangular position. The locking system comprises a securing element 1010,a clamping nut 1077 and a stabilization pin 1093. As discussedpreviously, the securing element 1010 includes a head portion 1088 and ashaft portion 1089 that extends through the recess 1082 in thereceptacle 1054. As shown in FIG. 11B, the securing element 1010 thenextends into an opening 1078 formed through the clamping nut 1077.Portions of the upper endplate 1020 are positioned between the securingelement 1010 and the clamping nut 1077, such that rotation of thesecuring element 1010 draws in the clamping nut 1077, causing themembers to clamp and secure the upper endplate 1020 in a desired angularposition.

The clamping nut 1077 includes an opening 1078 for receiving thesecuring element 1010 therethrough. In addition, below the opening 1078is a lower recess 1079 for receiving a stabilizing pin 1093, which isdiscussed in more detail below. As shown in FIG. 11B, the clamping nut1077 comprises a ridged outer surface. The advantage of the ridged outersurface is that as the clamping nut 1077 abuts the upper endplate 1020(which could be formed of PEEK), the ridges bite and dig into endplate1020, thereby creating a better engagement between the two components.

In addition to the securing element 1010 and the clamping nut 1077, thelocking system comprises a stabilization pin 1093. In some embodiments,the stabilization pin 1093 comprises a Woodruff key. The stabilizationpin 1093 is configured to extend through the recess 1082 and into thelower recess 1079 of the clamping nut 1077. The stabilization pin 1093advantageously serves as a counter or anti-torque to prevent theclamping nut 1077 from rotating. As shown in FIG. 12, the stabilizationpin 1093 can comprise a cut-out portion 1094 that is designed to engagethe head portion 1088 of the securing element 1010, which advantageouslyhelps to steady the stabilization pin 1093 during use.

In addition to the locking system that secures the angulation of theupper endplate 1020, the implant 1000 comprises a separate lockingsystem that restricts relative movement between the inner member 1012and the outer member 1014. This locking system comprises a lockingmember 1080 and a lock ring 1081. The lock ring 1081 is designed tointerdigitate with and engage the gear member 1016. The locking member1080 comprises a protrusion, nub or tab 1082 that is designed to fitwithin a recess 1083 of the lock ring 1081. When an expansion tool isnot operating the implant 1000, the protrusion 1082 of the lockingmember 1080 resides in the recess 1083 of the lock ring 1081, therebyrestricting movement between the inner member 1012 and outer member1014. When an expansion tool is inserted into the implant 1000, itpushes in the locking member 1080 such that the protrusion 1082 ispushed out of the recess 1083, thereby allowing relative movementbetween the inner member 1012 and outer member 1014.

FIG. 12 illustrates a side cross-sectional view of a polyaxial endplateassembly of the implant of FIGS. 11A and 11B. FIG. 13 shows a topcross-sectional view of the polyaxial endplate assembly of FIG. 12. Fromthese views, one can see how the locking system including the securingelement 1010 and the ridged clamping nut 1077 are configured to securethe upper endplate 1020 therein.

The polyaxial endplate assembly of FIG. 12 can have differentangulations. The upper endplate 1020 is capable of angulating relativeto a horizontal plane along 360 degrees. In some embodiments, the upperendplate 1020 can angle between 0 and 45 degrees. In other embodiments,between 0 and 30 degrees. And in yet other embodiments between 0 and 15degrees. Advantageously, the polyaxial endplate assembly conforms to thenatural anatomy of a patient, thereby saving time on the part of thesurgeon who would no longer have to guess at which type of implant toinsert into a patient. In addition, by conforming to the natural anatomyof a patient, the polyaxial endplate assembly evenly distributes load,thereby reducing stress concentrations that would could occur innon-conforming endplates.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims. Althoughindividual embodiments are discussed herein, the invention covers allcombinations of all those embodiments.

What is claimed is:
 1. An expandable vertebral implant assemblycomprising: an inner member; an outer member; a gear member, whereinrotation of the gear member causes relative movement between the innermember and the outer member; and a polyaxial endplate assembly attachedto at least one of the inner member and the outer member.
 2. Theassembly of claim 1, wherein the polyaxial endplate assembly comprisesan endplate.
 3. The assembly of claim 2, wherein the endplate is capableof having between 0 and 30 degrees of angulation.
 4. The assembly ofclaim 1, wherein the polyaxial endplate assembly comprises an endplate,a securing element, and a clamping nut.
 5. The assembly of claim 4,wherein the securing element is capable of rotating into the clampingnut to thereby secure the polyaxial endplate therebetween in a desiredangulation.
 6. The assembly of claim 4, wherein the clamping nut isridged.
 7. The assembly of claim 1, wherein the polyaxial endplateassembly comprises an endplate having a plurality of spikes and teeth,wherein the spikes are taller than the teeth.
 8. The assembly of claim1, wherein the polyaxial endplate assembly comprises a receptacle forreceiving an endplate therein.
 9. The assembly of claim 8, wherein theendplate has an outer wall of splines.
 10. The assembly of claim 1,wherein the polyaxial endplate assembly comprises an endplate having anouter wall of splines.
 11. An expandable vertebral implant assemblycomprising: an inner member; an outer member; a gear member, whereinrotation of the gear member causes relative movement between the innermember and the outer member; a polyaxial endplate assembly attached toat least one of the inner member and the outer member; and a fixedendplate assembly attached to the other of the inner member and theouter member.
 12. The assembly of claim 11, wherein the inner memberincludes outer threads that are capable of engagement with inner threadsof the gear member.
 13. The assembly of claim 11, wherein the polyaxialendplate assembly comprises an endplate capable of angulation.
 14. Theassembly of claim 13, wherein the endplate is capable of between 0 and30 degrees of angulation.
 15. The assembly of claim 13, wherein theendplate comprises one or more spikes and one or more teeth, wherein theone or more spikes have a height greater than the one or more teeth. 16.The assembly of claim 13, wherein the endplate comprises an outer wallof splines.
 17. The assembly of claim 13, wherein the polyaxial endplateassembly further comprises a securing element and a clamping nut. 18.The assembly of claim 17, wherein the securing element is capable ofrotation through the clamping nut to fix the endplate in position. 19.The assembly of claim 11, wherein the polyaxial endplate assemblycomprises an endplate and a receptacle for receiving the endplate. 20.The assembly of claim 19, wherein the polyaxial endplate assemblyfurther comprises a stabilization pin received through a recess formedin the receptacle.